'\" t
.\"     Title: pam_wheel
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: 09/03/2021
.\"    Manual: Linux-PAM Manual
.\"    Source: Linux-PAM Manual
.\"  Language: English
.\"
.TH "PAM_WHEEL" "8" "09/03/2021" "Linux-PAM Manual" "Linux\-PAM Manual"
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.SH "NAME"
pam_wheel \- Only permit root access to members of group wheel
.SH "SYNOPSIS"
.HP \w'\fBpam_wheel\&.so\fR\ 'u
\fBpam_wheel\&.so\fR [debug] [deny] [group=\fIname\fR] [root_only] [trust] [use_uid]
.SH "DESCRIPTION"
.PP
The pam_wheel PAM module is used to enforce the so\-called
\fIwheel\fR
group\&. By default it permits access to the target user if the applicant user is a member of the
\fIwheel\fR
group\&. If no group with this name exist, the module is using the group with the group\-ID
\fB0\fR\&.
.SH "OPTIONS"
.PP
\fBdebug\fR
.RS 4
Print debug information\&.
.RE
.PP
\fBdeny\fR
.RS 4
Reverse the sense of the auth operation: if the user is trying to get UID 0 access and is a member of the wheel group (or the group of the
\fBgroup\fR
option), deny access\&. Conversely, if the user is not in the group, return PAM_IGNORE (unless
\fBtrust\fR
was also specified, in which case we return PAM_SUCCESS)\&.
.RE
.PP
\fBgroup=\fR\fB\fIname\fR\fR
.RS 4
Instead of checking the wheel or GID 0 groups, use the
\fB\fIname\fR\fR
group to perform the authentication\&.
.RE
.PP
\fBroot_only\fR
.RS 4
The check for wheel membership is done only when the target user UID is 0\&.
.RE
.PP
\fBtrust\fR
.RS 4
The pam_wheel module will return PAM_SUCCESS instead of PAM_IGNORE if the user is a member of the wheel group (thus with a little play stacking the modules the wheel members may be able to su to root without being prompted for a passwd)\&.
.RE
.PP
\fBuse_uid\fR
.RS 4
The check will be done against the real uid of the calling process, instead of trying to obtain the user from the login session associated with the terminal in use\&.
.RE
.SH "MODULE TYPES PROVIDED"
.PP
The
\fBauth\fR
and
\fBaccount\fR
module types are provided\&.
.SH "RETURN VALUES"
.PP
PAM_AUTH_ERR
.RS 4
Authentication failure\&.
.RE
.PP
PAM_BUF_ERR
.RS 4
Memory buffer error\&.
.RE
.PP
PAM_IGNORE
.RS 4
The return value should be ignored by PAM dispatch\&.
.RE
.PP
PAM_PERM_DENY
.RS 4
Permission denied\&.
.RE
.PP
PAM_SERVICE_ERR
.RS 4
Cannot determine the user name\&.
.RE
.PP
PAM_SUCCESS
.RS 4
Success\&.
.RE
.PP
PAM_USER_UNKNOWN
.RS 4
User not known\&.
.RE
.SH "EXAMPLES"
.PP
The root account gains access by default (rootok), only wheel members can become root (wheel) but Unix authenticate non\-root applicants\&.
.sp
.if n \{\
.RS 4
.\}
.nf
su      auth     sufficient     pam_rootok\&.so
su      auth     required       pam_wheel\&.so
su      auth     required       pam_unix\&.so
      
.fi
.if n \{\
.RE
.\}
.sp
.SH "SEE ALSO"
.PP
\fBpam.conf\fR(5),
\fBpam.d\fR(5),
\fBpam\fR(8)
.SH "AUTHOR"
.PP
pam_wheel was written by Cristian Gafton <gafton@redhat\&.com>\&.
